Telegraph system



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8 Sheets-Sheet 1 J. HERMAN TELEGRAPH SYSTEM Filed Feb; 28,, 19%;

Feb. 22,1927.

INVENTOR v ATTORNEY Feb. 1 J. HERMAN TELEGRAPH SYSTEM Filed Feb. 28, 1924 8 Sheets-Sheet, 2

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i l l l l lHl r INVEMOR J Hen/22w I ATTORNEY 22 1 2 Feb 9 7 J. HERMAN TELEGRAPH SYSTEM Filed Feb.

' INVENTOR J. man/ 8 Sheets-Shet Z5 BY A TTORNE Y 1 618 193 Feb. 22, J. v I

'TELEGRAPH SYSTEM Filed Feb. 28, 1 24 8 Sheets-Sheet 4 l l l lH LINVENTOR H-I-I I H Feb. 22,1927. 1,618,193

J. HERMAN TELEGRAPH SYSTEM Filed Feb. 28, 1924' a SheetS -Sheet e J berman/ ATTORNEY Feb. 22, 1927.

- I J. HERMAN TELEGRAPH vSYSTEM- Filed Feb. 28, 1924 8 Sheets-Sheet 8 5 .3% g m gw A? A N INVENTOR J Han/22 w v ATTORNEY Patented Feb. 22, 1927.

UNETEE STATES 6 19 as i arias.

. a'o'snrn HERMAN, on NE YORK, N.-Y., nssienon T0 AMERICAN TELEPHONE AN TELEGRAPH ooiarAnY, A GORP'OR-A'JJIGN osnnw YORK.

TELnGRArn SYSTEM.

Applicationfiled February 28,1924. Serial at. sew/s7.

A principal object of my invention is to provide a new and improved system of telegraph signaling. Another object of my invention is to provide for telegraph signaling by means of a code employing currents of several different magnitudes. Another object of my invention is to provide for efiicient magnitude discrimination among the current impulses in telegraph signaling. Another object is to increase the signaling speed in a message channel by employing a considerable number of current magnitudes on the line. Still another object of my; invention is to provide for economy of line time by the use of a code employing several different current magnitudes with effective discrimination between them. These objects and various other objects of my'inventio n will become apparent on consideration of a limited number of embodiments which are illustrated inthe accompanying drawings and described in the following specification.

It will be understood that the following disclosure relates to these particular examples of the invention and that the invention will be definedin the appended claims.

Referring to the drawings, Figure 1 is a diagram of a two-channel system employing five distinct current magnitudes and using neutral relays at the receiving station; Fig. 2 is a diagram of a similar system except that polar relays are employed at the receiv ing station; Fig. 3 is a dia ram showing two channels thrown into a single message channel; Fig. 4 is a diagram showing the utilization of two channels in another way forsend ing a single message; Fig. 5 is a diagram showing a modification fora bridge polardupl'ex line; Fig. 6 is a. diagram showing an embodment of my invention in connection with a carrier current system; Fig. 7 isv a diagram corresponding to Fig. 6'but with the addition of discrimination as to reversals of the carrier current; Fig. 8 is a diagram similar to that of Fig. 7 but with transmissionon each of two carrier currents in quadrature; Fig. 9, 10, 11 and 12 show. punched tapes such as may be employed with the systems of the foregoing figures.

ie'f'erring to Fig. 1, this shows a transmission line with means at the sending sta-' tion to connect it alternately for two different channels which may be distinguished phannel A and channel B. The altere'urreut generator 21 sends its current to the relays D and E. \Vhile the line is connected to contact A the battery 0 is connected to contact 3,, and an instantlater while'the line is connected to contact B the battery C is connected to contact A 7 Transmission is effected by means of a prepared tape as shown in Fig.9. Five different current impulses can be piit on the .lineat the sendingstation, namely current of magnitudes 0, +1, 1, +2 and %-2.. These are determined, respectively, by different code combinations punched in the tape of Fig. 9. v At the same time that the line is connected for channel A at contact A the battery C isconnected to energize the tape feed magnet 22 inthe tape transmitter B of channel B. Thus, contacts are established at B, in accordance with the holes punched in the. tape for channel B, and the corresponding relays M M and P are energized (or not energized) accordingly. I

New upon the next current reversal from generator 21 the contact of the battery 0 is shifted from 13 to A, and 'the connection of the line is shifted from A, to B Accordingly, for the duration of the contact at 13,, a currentimpulse will be sent over the line from the battery F whi'ch will be plus or minus as the relay'P is energized or not energizech and will be of magnitude 1 when relay M but not M energized, and will be of magnitude 2 when relay M is energized. Also, the casemust be held in View that if neither relay M nor M isenergized, the current will be of zero magnitude. 1

The tape transmitter employed maybe of the wellknown used in printing telegraphy,

tion, while animpulse or one of five ma nitudes is being sent over the line for one It will be seen that at the sending sta- 7 channel, readjustments are being made for the other channel to determine the succeeding impulse to go over the line- Thus there is no lossot line tune in setting up the code combinations at the sending station. As V already'pointed out, each current impulse ens fire difijarent current channel two successive units of line time may be employed generally to transmit a letter or corresponding symbol, and that exceptionally three units may be required, one of these being for the shift combination.

At the receiving station the current goes through four relays in series. One'of these is a polar corrector which is relied upon to establish synchronous reversals from a source of current to the relay N. The associated synchronizing apparatus designated 23 is, familiar in the art of printing teleg rapliy and will not be described here. Suf- V lice it to say that the relay N is operated in synchronlsm with the sending relay E. Relay N, operates on any normal magnitude of I current other than zero. Relay N, is-marginal and operatesonly on current of magnitude 2.

To illustrate the operation of the receiving statioin assume that a positive current of magnitude 2 is received over the line in channel A. At this time the relay N will connect thebat-tery L with contact A 0-perating switch S to close thecontacts controlled thereby. The relay Q is a polar relay which closes on the, contact marked (.l) or the contact marked according as the current through it is plus or minus. Hence the impulse of positive current of magnitude 2 that we are considering will. shift the armatures of all three relays N N, and Q from the positions shown in Fig. 1. (If the current had been of magnitude 1, relay N, would have operated but not N Relays N, and N, operate alike for positive and negative impulses but Q, will operate as described only for positive impulses.)

Accordingly, a circuit is established from ground, through the armature of relay Q, armature of relay 0 (on its back contact, because the circuit for O is open at the armature of relay N through conductor 24., contact of switch S to the winding of plunger 25 and battery J. This produces a corresponding perforation in the receiving tape for channel A.

Another circuit may be traced from ground, through the armature of relay N,, armature of relay N conductor 24", corresponding contact ofswitch S, and winding of plunger 27--to battery J. This causes a corresponding hole to be punched'in the receiving tape.

If the current had. been negative and of magnitude 1, the circuit of plunger 25 would have been open at relay Q. Also, the cir cuit of plunger 27 would have been open at relay N, but the circuit of plunger 26 would have been closed through the back contact of relay N, and the front contact of relay N in this case a hole would have been punched at the middle position on the receiving tape. p

If no current had been transmitted, in other words for current magnitude zero, the armature of relay N, would have remained on its back contact so that neither plunger 26 nor 27 would have been energized. But since relay Q is of the polar type, it might have remained on its plus contact; however, relay 0 would be energized at such time and would open the circuit for the plunger 25 at this point evenlthough it might be closed at relay Q.

W hen the relay E at the sending station changes the connection from contact A, to

contact B the relay N at the receiving station changes the connection of battery L from contact A, to contact 13,. Accordingly, switch S, opens and switch S closes. Thus while the perforators for channel B are being operated, those for channel A are releasing due to the opening of the switch S and the corresponding tape feed magnet 42 is also energized from battery L to step the tape for channel A ahead in readiness for the next received impulse in that channel. Following the convention suggested in connection with the description of the sending station, two successive impulses may represent any one of twenty-five characters and. accordingly, the two successive impulses as recorded in two successive combinations,

on the receiving tape -may be read directly by one familiar with the code, or tlie tape can be put through a printer to print the message according to well known practice.

Referring to Fig. 2, this shows a sending station like that of Fig. 1. except that here seven different current magnitudes are employed instead of five, these seven current magnitudes being 0, +1, l, +2, 2, 3 and 3. Fig. 2 marked 43 and 44 corresponds to the apparatus in the like designated dotted rectangles of Fig. 1 except for the change to take care of the extra current magnitudes +3 and -3.

The sending or receiving tape forl igi 2 will appear as shown in, Fig. 10, with a transverse row of four holes (or positions for holes) for each current impulse, that is, for each unit of linetime. For the seven different current strengths'on one impulse, forty-nine combinations will be possible on two successive impulses Accordingly, two successive impulses will give a code of fortynine different letters'or symbols which will be adequate for many purposes. I

On some telegraph circuits, Where the reltll) iii) The apparatus in the boxes of i ceived currents are rather small, it may be' desirable to use sensitive polarrelays instead of neutral relays for the magnitude discrimnations at the receiving station. One advantage-of polar re'lays over neutral relays .lies ii the fact that the operating and non- 'of the biasing windings is shunted by an achustable res stance. For three ot the SIX receiving relays the biasing current goes one wayand for the remaining three it goes the other way, so that the relays 31, 32 and 33 will respond only to positive impulses, While the relays 31, 32. and. 33 willrespond only to negatives impulses. The armatures for all six of these relays are shown. in Fig. 2 in their non-operated positions. It will be seen that' each pair of non-operated contacts for positive and negative relays of corresponding magnitudeabove the first magnitude are connected together Eachoperated contact of a relay which operates on one polarity is connected to the armature of the next higher. relay'of the same polarity, and

the operated contacts of the highest magni tude=relays are connected together. For-any positive impulse the armature of V the negative relay 3l"will be 011 its nonoperated contact and the armature of the positiverelay'31 will be on its operated con- .tact. The circuit of the plunger 25 (coinpare the boxes 25 in Figs. 1 and 2) as determined by switch S, or S for channel A or channel B will then be madefromground,

through the armature of relay 31' and through theback contact of relay (because relay 0 will be deenergized at this time due.

to the energization of relay 31). On the othershand, when the current is negative,

relay 0 will be energized, opening-the circuit for the plunger determined by the switch.

7 S, or S The operation of the other plungwill be opened by relay O.

as of the perforators will be evident from the diagram and from the description that has been given for Fig l. TlVhen the line current is Zero, the armatures of both relays 31 and 31 will have'the positions shown in F ig. 2 and hence the circuit of the plunger The tapes punched at the receiving end in the two channels'of Fig.2 will be as indicated in Fig. and they may be read directly by one familar with the code or they may be put through a printer according 'to' well known practice.

' Whereas Figs.' 1 and2 provide for multiplex transmission, that lS,.fO I the transmission of two messages n the. same direction. by alternately'connecting the line forterposed resistances,

one channel or the other, Fig; 3 discloses a modificatipn to utilize, the line, time efitective- '13 for single'chaniiel. At th sending station, a two-ring'distributor is shown, each of the rings being developed in the drawing a cording to a t niillar conventiqn- T ringv 3d controls the connection 'tofthe line circuit,taking the place of the relay E in Figs. 1; and 2LThe ring 35 controls local switching arrangements. as. will appear preseiitly. I

In a general way, the sending selector relays ojt Fig. .3 aresimilar to those for Figs.

1 and 2, with the addition that in F ig. 3

locking circuits are, introduced. Another .difiference is that the different current magnitudes are determined by the application of difierentbattery strengths instead of by ini As shown in Fig. 3, the sivtichesv have just opened; after being closed b contact of the segment f Wi the brush X2. According to the colllbination in the tape at 22', the magnets P, M and M at the right have just been energized and, have locked up at P", M' and M or some.

of these, through the locking circuit from b attei'y- H and throughthe back contact of relay D As shown in Fig. 3, only relay :M is locked: up to correspond with the code for. current 0t strength -1. The, relay 41 is energized whenever any one of the relays 1?, M, or M is energized. Accordingly the circuit is, establishedwhichcan readily .be traced as follows from, ground through the -1. part of-battery F, back contact of 1 relay P, front contact olirelay' 'M front contact of relay 4.1, distributor segment B brush X tothe line. i

- At the same time that this circuit is es-,

tablishecl- ,*brush X isengaged by distributor segment 0 and connects, the battery 28 to relay D operatingits armature to the'position shown in Fig.3. Accordingly, at this armature, the. locking circu t of the. selector relays of channel A are opened and the combination which had previously been transmitted to the line for channelA is released. Also, the armature of relay D connects ground toclose the circuit for the tape feed magnet 22 and the tape is steppedahead one,

step. 1

lVhen the distributor Segment B has passed about half way under the brush X,.

the switches S tofclose, so, that the combination established in the tape transmitter in the preceding quarter-cycle (while segment 0 engaged brush 'X is'now 'put into the relays ]?,'M or M or some of these, for channel A. and this combination is locked upin the windings P, M .or M or some of these, and the, armatures of these relays are the segment 0 leaves the brush X. and the segment cl engages the. brush X -Th1S [causes the relay D to deenergize and causes o open, leaving the in the windings P,

same time the segment A, engages the brush X, and the corresponding impulse is put on the line.

At the receiving station. the current from the line passes through the relays in series just as for Fig. 1. During the transmission in channel B, the impulse being 1, the armature oit relay Q will be thrown to the open circuit condition but the armature of relay N will close, thus establishing a circuit from At this time the brush Y, applies the battery 29 through the distributor segment 13,, to the switch S so that the conductor 2%. is connected to the corresponding winding of one readily perceived by noticing of the'relays' The two armatnres of this relay to then lock up through one of the corresponding windings 39, the armature of relay D being on its back contact at this time. Thus it will be seen that the received current impulse of strength 1 has in the A channelas for the B channel.-

opened and the switch S is closed.

its effect stored up: in the corresponding relay 39. I

' At the same time that the brush'Y engages the distributor segment 13,, the brush Y goes into engagement with distributor segment 0, thus applying the battery 30 to actuate the switch S WVhilethe brush Y, was in engagement with distributor segment A combination was stored up in the armatures for the storing relays \Vhatever this combination was, the closure of the switch S closes the corresponding circuits to the perforator 15 and the tape is perforated accordingly. Then when the brush Y is engaged by the distributorsegment d, the switch S5 opens and the relay D is energized, putting ground to the tape feed magnet 42 and stepping the tape along one step. When the brush Y, passes from engagement with distributor segment B to segment A the switch S is combination set up and locked up in the storjust as has As explained for Fig. 1, a convenient code may be made up by'employing two successive combinations on the tape to give twenty-five different resultant combinations. It will be seen that-the system of Fig. 3 provides for a' single message channel but it provides for very rapid sending. While one combination-is being sent as an impulse on the line, the next combination is being ground, through conductor 2%.

' ated apparatus from Fig. 0

has just been described 'means of the segment A. of the The i at the right remams pulses,

of three is to be compared with a group of three in Fig. 1. Just as for Fig. 1, three .holes of the tape of Fig. 11 give five different combinations. The remaining three holes of the same position on the tape give five combinations and the complete set of 81X holes gives twenty-five combinations which may conveniently represent the characters to be-transnntted by resorting to a lme shift to ct one of the less used char acters.

A complete cycle on the line may be the distributor rings 34 and 35. in such a cycle there are four units of line time. The ring 35' in Fig. 4 and its associated apparatus'are the same as for the ring 35 and its associin Fig. 3. But the ring 3 1' in Fig. e may by ments A and and duplicating the associated apparatus. Thus the three dotted rectangles of Fig. 3 designated 47, 4:8 and 49 will be found each duplicated in Fig. 4-. Accordingly, itwill'be seen that for the biseoting each of the segtwo combinations side by side in the tape of Fig. 4t, two respective successive current impulses will be put on the line,.the first'by ring'g l the second by means of the segment A ofthe ring 34. f

At the receiving station, comparing Fig. 1 with Fig. 3, it will be seen that the segments A an 1 B of the distributor ring- 36 of Fig. 3 have each been bisected as seen in Fig. 4 and that the selector switches controlled thereby have been duplicated, that is,

S, and S in Figfl take the place of S,

in Fig. 3, etc.

'As shown in Fig. a, transmission on the 15 channel has just started and will be followed by transmission on theB" chann'el.. The corresponding combinations will' be stored in the B and B apparatus, respectively, at the right in Fig. 1, and at the end of the transmissionof those two imthe switches S, will be closed and both combinations will be punched simultafneously and side by side in the'tape bythe perforator. With the foregoing explanation it isthought that the-operation ofthe apparatus of Fig. 4 will be entirely obvious after the disclosure that has been given in be looked upon as derived B of the ring 34 of Fig. 3,

ill)

connection with the drawings. g Referring to Fig. 5, this shows abridge preceding figures of the polar-duplex telegraph circuit adapted for transmission with five magn'itudes of 'current, namely,"O, +1, 1 +2 and 2. The

impedance to ground at the terminals must remain constant so as not to affect the duplex balance at the distant station. Therefore,

'it is not practicable to obtainthe difl'erent current magnitudes by the use of resistances such as R and R 'in Fig.1, and the different I currentmagnitu'des are obtained by employing different battery "strengths; as already explained for Fig. 3. The auxiliary relay 41 is'provided to establish a ground connection for zero current transmission. It

I will be -'nc'iti-ced that the relay 41 connects the selector rel'a line to ground only when" non operated, which-condition "occurs when none of the selector relays "is operated. Incase a selector relay is-operated, however, theflcurrent fiowingfrom battery G through the operating or holding windings of that particular W1ll also flow through the windings' ot relay 4:1 and will disconnect the line from ground and connect it to the selector relay contacts. 1 I

At the receiving end, the various receiv ing relays are connecteda'cross the bridge points of the duplex set, as clearly shown in the drawing, "and beyond this stage the operation is, the same as for Fig.1.

Fig-.- i6'sl1ows the application of inyinv'en tion' in "connection with a carrier current system. Polarity discrimination is not employed in' this'case but four different current magnitudes are used, namely,'0, 1 Qand A tape is used such as that shown in Fig.

'12. The essential difl'erence' from the earlier disclosi'ires of this specification lies in the application of the current to ltheline, the selector relays being operated the same asinthe disclosures that have been made heretoforew The carrier supply c'u'rre'nt'is relays corresponding to the receiving'relays on the line in Fig. 1.

Fige 7 shows my invention in connection with a carrier current system with provision; In'this system employed and for polarity discrimination, a tape like-that of Fig; 91s fire current magnitudes are involved, namely 0, +1," 1 +2 and 2. ItWill readily be see n' thatthe olaritydetermining relay A and phase B.

The Oi1tgoes through duced that the proportional to the reciprocal of 04) varies,

determines the phase "of the carriercurrent,

putting on a currentof one phaseor another of opposite phase according as the relay is operated or non-operated.

Atthe receiving station there is a local supply of alternating currentin phase with the carrier supply at the sending endthe.

synchronism being established "and maintaincd by methods well known in the art of carrier current telegraphy'. Both the received current and the local supply of current are applied to a detector of the pushpull type and the phase reversal in the current received from the line give-reversals of the current in the receiving relay windings.

The circuits controlled bythe receiving relays are the same as already described for."

Fig. 1. p r s I Referring to Fig. 8, thisshows a system in which two carrier current channels of the same frequency are employed byusing two carrier currents "90 degrees apart iinphase. These are referred to "in F ig. 8 as phase is controlled as shown in Fig. 71and' the tape employed is of thevkind shown in Fig. 11. The hybrid coil or three-winding transformer T is employed at the sending station to Each of these phases combinethe transmitted currents of the two phases. In this way each of those currents is prevented from feeding back in the generator circuit of the other current. The

transmission is by means of a tape, trans-' mitter corresponding to the 'tap'eof Fig. 11: At the receiving station there are two local currentsupplies, respectively inphase with thecarrier 'supplies A and B the sending station. Res ective push-pull "detectors are used and in each of them the current in phase addsto or subtracts from the local sup'plyto give-an efiFective indication. in the outpu tcircuit, while the current in quadrature is of only "negligible effect 5 to vary the magnitude of the detector output currents. The circuits controlled by the relays in the detector output circuits lead to 'a' perforato'r corresponding to the kind of tape shown in Fig.1}

In accordance with my invention, tude discrimination I is employed to increase the speed in a telegraph circuit or rather than to increase the; number of messages that can be transmitted. simultane ously. 'Ifflthe tudes of current that can be employed altern'atively in a unit of' line time is n, and

the number: of

letters or characters to be distinguished is P, then" the number m of units of line'time that will be necessaryjfor a' letter or character will be given by the equation 7%;1 from which is readily despeed of the line (which is as log n. This is thelaw of the increase or magni;

channel number of diflerent ma'gni current impulses hav ng any one of having anyone of current values, and at the sending speed and connecting these sets of apparatus to in a single channel attainable by increasing the magnitude discrimination in that channel.

If instead of getting the highest possible speed in a single message channel, it is'desired to increase the number of message channels by magnitude discrimination, this can readily be accomplished by the use or" the multiplex system with distributors. Thus referring to Fig. 1, instead of the relays E and D connecting the line alternately to two channels, distributor rings could be employed connecting to any number of channels.

' I claim: v

1. The method of telegraph signaling by means of a singlemessage train oi impulses which consists in transmitting successive current impulses ot-said train, each impulse having any. one oi n different magnitudes Where n is a number greater than 3, and at the sending end preparing one set of apparatus for sending one impulse while another set of apparatus is sending the preceding impulse of the same message train the line in cyclic succession.

'2. The methodof telegraph signaling by means of a single messagetrain oi": impulses which consists in transmitting successive current impulses of said train, each impulse having any one of 41- different magnitudes where a is a number greater than 3,- and at the receiving end registering one impulse in one set of apparatus while another set of: apparatus is being prepared to receive the next succeeding impulse of the same message train and connecting these sets of apparatus to the line in. cycle succession.

, 3. The method vottelegraph signalingby means of a single message train of impulses which consists in transmitting successive of said train, each impulse n diliferent magnitudes where n-is a number greater than 3, and at the sendingend preparing one set of appa ratus for sending one impulse while another set of apparatus is sendingthe preceding impulse of the same message train and at the receiving end registering one impulse in one set ot apparatus while another set 01 apparatus is being prepared to receive the next succeeding impulse of the same message train and connecting the sets of apparatus to the line at the sending and receiving ends -in cyclic succession at each end," and in synchronism at both ends.

4. The method of telegraph-signaling by means of a slngle message train of 1mpulses which consists in transmitting successive current impulses of said train, each impulse ing up a'relay combination to determine the current value of one impulse while the at least four different end lockimpulse While the previously received impulse of the same message train is being perforated from another set of relays locked up to correspond thereto, and operatively connecting the said sets of relays with the line in cyclic succession. 1 c r 6. The method of telegraph signaling which consists in transmitting successive current impulses, each impulse having any one of several different magnitudes, ing end preparing one set of apparatus for sending one impulse while another set of duplicate apparatus is sending the preceds ing impulse of the same message train and connecting these sets of apparatus to the line in cyclic succession. v i I 7. In combination, a line, two duplicate sets of sending apparatus associated therewith, means to adjust these sets one at a time according to impulses of a single message train to be sent, and means alternately to connect them to the impulses.

8. The which consists .in transmitting successive cu rent impulses, each. impulse having any one of several different magnitudes, at the receiving end preparing one set oi: apparatus for recording according to a received impulse while another set of duplicate appara tus is recording the preceding impulse of the same message train and connecting these sets;

rent impulses, each impulsehaving any one of several different magnitudes, at the sending end preparing one set. V of apparatus for sendingone impulse while another set ofduplicate apparatus is sending the preceding impulse of the same message train and connecting vthese sets of apparatus to the line cyclic succession, and at the receivat the send line to send such" .method 0f telegraph signaling 10. The method of telegraph signaling. which consists in transmitting successive-curing end preparing one set of apparatus for recording according to a received impulse While another set of duplicate apparatus is recording the preceding impulse of the same message train, and connecting thesev sets of receiving apparatus to the line in cyclic succession and in synchronism with the connection of the said sets of sending apparatus. I

11. In combination, a line, two duplicate sets of sending apparatus associated therewith, means to adjust these sets respectively one at a time according tosingle impulses of a single message train to be sent, means alternately to connect them to the line to send such single impulses, also two duplicate sets of receiving apparatus associated with said line, means to connect these sets with the line one at a time in synchronism with the connectionof the said sets of sending apparatus and thereby adjust them respectively according to single impulses received from the line, and means alternately torecord from the sets according to the adjustments therein.

In testimony whereof; I'have signed my name to this specification this 26th day of February, 1924. a V

' JOSEPH HERMAN. 

